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ATPL 21 AIRCRAFT GENERAL KNOWLEDGE – AIRFRAME AND SYSTEMS |
| 21.07 FUEL SYSTEMS |
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1
The hydraulic oil, entering the hydraulic pump, is slightly pressurised to :
Prevent cavitation in the pump |
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2
Discounting the possibility of leak, the level in a hydraulic reservoir will :
Fluctuate with jack displacement and accumulator pressure. |
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3
The ram air turbine (rat) provides emergency hydraulic power for :
Flight controls in the event of loss of engine driven hydraulic power. |
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4
To allow for failure of the normal method of system pressure limiting control, a hydraulic system often incorporates
A high pressure relief valve. |
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5
In hydraulic system, a shuttle valve :
Allows two possible sources of pressure to operate one unit. |
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6
(for this question use annex 021-6736a) the schematic diagram annexed illustates a jack and selector valve in a typical hydraulic system. assuming hydraulic pressure throughout :
A condition of hydraulic lock exists and no movement of the jack will take place. |
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7
An accumulator in a hydraulic system will :
Store fluid under pressure. |
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8
Assuming a hydraulic accumulator is pre- charged with air to 1000 psi. if the hydraulic system is then pressurised to its operating pressure of 3000 psi, the indicated pressure on the air side of the accumulator should be :
3000 psi. |
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9
Internal leakage in a hydraulic system will cause :
An increased fluid temperature. |
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10
Assuming an accumulator is pre- charged with air to 1000 psi and the hydraulic system is pressurised to 1500 psi, the accumulator gauge will read :
1500 psi. |
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11
(for this question use annex 021-6716a) in the hydraulic press schematically shown, what balancing force would be acting on the right hand side ? (the diagram is not to scale)
100 n. |
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12
Hydraulic fluids of synthetic origin are:
Purple. |
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13
In hydraulic systems of large modern transport category aircraft the fluids used are:
Synthetic oil. |
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14
Hydraulic fluids must have the following characteristics: 1. thermal stability 2. low emulsifying characteristics 3. corrosion resistance 4. good resistance to combustion 5. high compressibility 6. high volatility 7. high viscosity the combination regrouping all the correct statements is :
1, 2, 3, 4 |
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15
In a hydraulic braking system, an accumulator is precharged to 1200 psi. an electrically driven hydraulic pump is started and provides a system pressure of 3000 psi. the hydraulic pressure gauge which is connected to the gas section of the accumulator, reads:
3000 psi |
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16
Where in a hydraulic system might overheat indicators be installed?
At the pumps. |
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17
Hydraulic fluids :
Are irritating to eyes and skin. |
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18
Hydraulic fluids used in systems of large modern airliners are:
Phosphate ester base fluids. |
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19
Large transport aeroplane hydraulic systems usually operate with a system pressure of approximately:
3000 psi |
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20
The type of hydraulic oil used in modern hydraulic systems is:
Synthetic oil |
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21
In a modern hydraulic system, "hydraulic fuses" can be found. their function is :
To prevent total system loss in case of a leaking hydraulic line. |
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22
In a the reservoir is pressurized in order to:
Prevent pump cavitation |
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23
The purpose of a shuttle valve is to:
Hydraulic pressure in hydraulic systems. |
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24
Shuttle valves will automatically:
Switch hydraulically operated units to the most appropriate pressure supply. |
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25
In addition to energy storage the accumulator of the hydraulic system is used :
For damping pressure surges in the system. |
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26
Hydraulic power is a
System pressure and flow. |
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27
The low pressure if
The pump output switch of a hydraulic circuit sets off an alarm : |
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28
For an aeroplane hydraulic supply circuit, the correct statement is : nitrogen) and destined to serve as a fluid or pressure reserve.
The security components comprise the filters, the pressure maintained under passes, and the fire shut-off valve. |
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29
The tanks of a hydraulic system are pressurized:
By bleed air coming from the turbine-engine. |
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30
The type of hydraulic fluid which has the highest resistance against cavitation is :
Synthetic fluid. |
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31
The hydraulic device similar to an electronic diode is a :
Check valve. |
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32
The component that transforms the hydraulic pressure into a linear motion is called
An actuator or jack. |
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33
The aircraft hydraulic system is designed to produce:
High pressure and large flow. |
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34
The function of the selector valve is to: parallel of two 12 volt/ 40 amphours batteries, will create a unit with the following characteristics. piston engine is of: (global output = thermal energy corresponding to the available shaft/power over the total thermal energy produced). ideal fuel/air mixture corresponding to a richness of 1 is obtained for a weight ratio of:
Communicate system pressure to either side of an actuator. |